class_docstr: Randomly decides who speaks next.
code: def set_characters(self, characters):
      self.characters = characters
  
imports: from typing import Optional, Dict
  import random
  from parlai.core.agents import Agent
  from parlai.core.opt import Opt
  from parlai.core.params import ParlaiParser
  from parlai.core.agents import create_agent_from_model_file
  from parlai.core.loader import load_agent_module
  from parlai.utils.logging import logging
label_desc: Use image node_id 1 for calling the RandomSpeakerDecicionsAgent obj's underlying member method code with example usage: obj.set_characters(characters) without return types